The example embodiments described herein relate to a semiconductor memory, and more particularly, relate to a memory module and a memory system.
A semiconductor memory device is a memory device which is fabricated using semiconductors such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), indium phosphide (InP), and so on. Semiconductor memory devices are classified into volatile memory devices and nonvolatile memory devices.
Volatile memory devices may lose stored contents at power-off. Volatile memory devices include a static RAM (SRAM), a dynamic RAM (DRAM), a synchronous DRAM (SDRAM), and the like. Nonvolatile memory devices may retain stored contents even at power-off. Nonvolatile memory devices include a read only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable and programmable ROM (EEPROM), a flash memory device, a phase-change RAM (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), a ferroelectric RAM (FRAM), and so on.